Rear backup cameras and surround vision/panoramic vision systems used in conjunction with interior rearview video mirrors and instrument panel/center console information screens (such as navigation screens) are known for use in vehicles. Examples of such systems are described in U.S. Pat. Nos. 7,859,565; 6,611,202; 6,222,447; 5,949,331; 5,670,935 and/or 5,550,677, which are hereby incorporated herein by reference in their entireties. It is known to display images captured by a rearward viewing imaging sensor or camera on a video display screen that is associated with or incorporated in an interior rearview video mirror assembly of the vehicle. Such interior rearview video mirror display screens typically have about a 3.5 inch or thereabouts diagonal dimension and a 4:3 or 16:9 aspect ratio, while instrument panel/center console screens (commonly used for navigational screens but also used and usable for displaying infotainment information or other information useful to the driver of the vehicle) typically have a larger diagonal dimension, often greater than about 6 inches diagonal dimension (such as 7.8 inches or thereabouts) and are used for likes of displaying map information and/or driving instructions and/or other information relating to vehicle features or functions. The smaller video mirror display screens are located in the interior rearview mirror assembly of the vehicle and thus are typically disposed in the vehicle at a location that is closer to the driver's eyes than other known or typical or conventional in-cabin and driver-viewable display screens, which are often disposed at the instrument panel or a central console or the like of the vehicle. Such instrument panel or a central console displays can be as large as 8.5 inch diagonal dimension (or even larger in some vehicles) whereas, because of the fit and function in the vehicle of the interior rearview mirror assembly, the video screen in an interior video mirror assembly is restricted in size to, in practical terms, a diagonal dimension of up to 4 inches or thereabouts.
It is also known to provide a surround view or “bird's-eye” view display (showing a representation of the vehicle from a top or bird's-eye view above the vehicle to enhance the driver's understanding of the areas surrounding the vehicle for use such as in parking maneuvers and the like) via a surround system vision such as a camera or vision system of the type shown in FIG. 1 (showing a vehicle 10 with a forward viewing camera 12, side-viewing cameras 14, 16 disposed at or in the exterior sideview mirror assemblies and a rearward viewing camera 18). Such a bird's-eye view or image or representation may be displayed on a 3.5 inch diagonal video mirror display and are typically displayed on larger (such as greater than about 5 inches diagonal dimension) display screens, such as larger display screens disposed at a center console or instrument panel of the vehicle, such as for displaying navigation information or infotainment information (such as radio or audio system information) and/or the like. In such conventional bird's-eye view displays, it is common and desirable, when executing a reversing maneuver, to display to the driver both the actual video images captured in real time by the rear backup camera of the equipped vehicle, and also to display to the driver a bird's-eye composite or synthetic view (sometimes called a top-down view) where the video images captured by the rear camera are combined with video images captured by a forward viewing camera, typically at the grille at the front of the vehicle, and by two exterior mirror-located cameras mounted respectively in the exterior sideview mirrors and having a field of view to the respective side of the vehicle. Examples of bird's eye view systems and associated techniques are described in U.S. Pat. Nos. 5,670,935; 6,636,258; 7,145,519; 7,161,616; 7,230,640; 7,248,283; 7,295,229; 7,301,466 and/or 7,592,928, and/or International Publication No. WO 2010/099416, published Sep. 2, 2010, and/or PCT Application No. PCT/US10/47256, filed Aug. 31, 2010, which are hereby incorporated herein by reference in their entireties. Conventionally, the bird's-eye view and view of the rearward images being captured by the rear-mounted camera as part of a rear backup aid are displayed on a single display screen, typically a center console display screen.
Recently, the Department of Transportation, National Highway Traffic Safety Administration (NHTSA) has issued a Notice of Proposed new Rule Making (NPRM). The caption of the NPRM is shown in FIG. 2 and aspects of the proposed Final Rule are summarized/captured in FIGS. 3-5. The NPRM was printed in the Federal Register: Dec. 7, 2010 (Vol. 75, No. 234), pages 76185-76250; Part IV, Department of Transportation, National Highway Traffic Safety Administration, 49 CFR Parts 571 and 585, RIN 2127-AK43, and titled Federal Motor Vehicle Safety Standard, Rearview Mirrors; Federal Motor Vehicle Safety Standard, Low-Speed Vehicles Phase-In Reporting Requirements; Proposed Rule, the entirety of which is hereby incorporated herein by reference. The NPRM at S6.2.1.1 requires and specifies a rearview image performance such that, when tested in accordance with the procedures in S14.1 through S14.2.3 of the NPRM, the rearview image shall display, in a location visible to a driver properly restrained by seat belts, a minimum of a 150 mm wide portion of each test object located at positions F and G in FIG. 5. Also, and in accordance with S6.2.1.2 of the NPRM, when the rearview image is measured in accordance with the procedures in S14.1 through S14.2.3 of the NPRM, (a) the calculated visual angle subtended by the horizontal width of the three test objects located at positions A, B, and C in FIG. 5 shall average not less than 5 minutes of arc; and (b) the angular size of each individual test object (A, B, and C) shall not be less than 3 minutes of arc.
As can be seen with reference to FIG. 7, in order to have a displayed object subtend a minimum of 5 minutes of arc angle, the display size of the target object (dependent on the distance of the displayed object from the driver's eyes) shown on the screen should be around 0.5 mm to 2 mm or thereabouts where the distance from the eyes of the viewer to the screen is between about 15 inches and about 50 inches.